Concentrates useful as additives in mineral oil compositions and mineral oil compositions containing same



Tenn W: Bishop; Plainfield; N. J., assignor to Tidewater Company, a-corporation of- Delaware PIQWlllg-i Application, March 27 7 1953-,

' 'Serial No. 345,221

40mi s. (Cl; 252-466;)-

Thepresenti invention relates to; improved mineral oil compositions and, more particularly, to such compositions of lubricating grade. Additionally, the invention relates tonovel-additive materials in the form of concentrates usefulqforincorporating, into mineraloils to impart certain desired properties there to,inclusive of imparting, tonsaidn oils improved: resistance against oxidation and undesirable ettectsthereof; and reducing the tendency of theoilsto corrode metals, such as bearing-metal alloys, in; contact therewith.

The; additive;v materials, contemplated herein are oilsoluble, substantially ash-free, phosphorusand sulfurcontaining products of reaction between (a) an ester of an propenoic acid and (b) an acidic, phosphorusand splint-containing product ofi reaction between a phosphor-11s sulfide and particulartypes of hydrocarbon mixtures. As is apparent from'the more detailed description of the: invention setforth hereinafter, the use, as

eactant iantcnaratiqaqf he. navel a d ti e mate ial oi an ester having the. unsaturated linkage present in propenoic acids, and an, acidic product derived from particular types of hydrocarbon mixtures described hereinafter, provides; highly effective; substantially ashless, anti-oxiemand anti-corrosion agents for mineral oils. Moreover, used such materials as reactants-enables preparation of highly efiective additives for mineral oils without need for resort to extensive processing operations, relatively high temperatures for reaction, and thelike.

With reference to the aforesaid ester reactant, alkyl esters of propenoic acids are particularly suitable, and more particularly, alkyl esters of acrylic acid. Still more specific illustrations includeacrylic acid esterified with an aliphatic alcohol of from oneto about eighteen United States Patent petroleum.

carbon atoms, such as in the series of alcohols ranging from methyl alcohol to octadecyl alcohol. Although such esters of acrylic acid are particularly suitable, the invention also contemplates use, as the ester reactant, of 'este-rs of 'homol'ogs of acrylic acid, such as crotonic ac d; aswell asesters of alkyl substituted propenoic acids, such asmethacrylicacid, ethacrylic acid, and the like.

aforesaid, the; acidic, phosphorusand sulfur-congaining reactant contemplated for use herein is a product of reaction between a phosphorus sulfide and a particular hydrocarbon mixture. In preparation thereof, phosph'brus pentasulfide is preferred for reasons of economy and commercial availability, Contemplated for use, however, are other phosphorus sulfides such as P283, P453, etci The particular type of hydrocarbon mixtures conte'iriplated for reaction with the sulfide for preparation of'the acidic reactant are mineral oils characterized by containing a substantial amount of more-aromatic type components capable of being solvent extracted from the oils by-use of selective solvents as well as the solvent extractsper se. Mineral oils containing a substantial amount of'more-aromatic type constituents readily separable from more-paraflinic type constituents by use of solvents that selectively extract the more-aromatic type constituents are known to those skilled in the art and 2,773,037 IFF-atented Dec. 4, 1956 are ely; us Q 1 n m a p e es ss n et r Sin su h,- e cte; solv n s. re n. thoseskilledimthetart, and, as noinvention is cla herein to solvent extractionprocesses per se, it. is, not; deemed essentialto describe them in considerable detail, For purposes'of illustration, however, conventional solvent extraction processes include those using solvents such as furfural, beta-beta-dichloroethylether, and phenol under conditions to preferentially extract the morearomatictype constituents from mineral oils containing same. In illustration, such selective solvents may be used in processing of a; varietyof types of; petroleum oils, examples of which include, oils derived from Continent, East Texas and othercrudes, and particula y lubricating oil fractions; and, deasphalted residua. ob tained from such crudes, Asa specific illustration with no intent of limiting the inventionthereto, the following data sets forth characteristics of anextract comprised predominantly of more-aromatic type components selec; tively. extractedfrom the more paratfinic type components from a Penn neutral oil by use of furfural as the selec-, tive solvent.

PROPERTIES OF FURFURAL EXTRACT Specific extinction coefiicient at 2600 A 58.8 Viscosity, SUSat 10 F --.9---?s-. ---s= -1. 1-8 G v ty, API l r a 8. .1 Molecular Weight (average) 31b The acidic phosphorusand sulfur-containing reactant may suitably be prepared by forming a reaction mixture of phosphorus; sulfi eand a par icular typeof: hydr carbon: mi ture as afcredefined; and reac ng th r acti n mixture. at an; elevated; temperature intthe presence. o ra suit ble ca a yst, g a Eriedeh after atalys Here ag i the art contains num rous; dis losures f pr pa a: tion methods for acidic, phosphorus: and. sul urrconmin n p ucts by reaction of; phosphor s lfide with hy o ar ons.- Sin e. n in ent on is cl imed. h r in o he cidic r actant, nor o. he p eparation er f, t i ls considered. unnecess ry tq desc ibe 51 9 1 P epa tions in detail herein. However, for purposes of illus; trati-on and not limitation, a particularly suitable acidic reactant for use in practice of this invention may be preparedby reactin in the presence ofasmall amount-of a Friedel-Craftscatalyst, areaction mixture of phose. phorus-sulfide and; a'hydrocarbon. mixture (e. g. solvent extract) and inwhich reaction mixture theamount of sulfide is preferably inexcess. of'the amount theoretically required to react with the hydrocarbon mixture. The reaction maybe carried out at an elevated temperature, e. g. to about 250 C., for about one to five hours; As a specific embodiment, suitable acidic, phosphorusand sulfur-containing reactants for use. in practice of this invention may be prepared by the process disclosed. in. my pc ng appl cation, er a N 309,1 filed. Sep 1 1 .5. .7- As s t rth; n, a idic produc nta n n ncr ase amounts o pho ph r s may be prepared by preparing a reaction mixture conining er ain e LCr t s a yst r a nc chl ri st n ic chloride, fe r c. h r d and from, out 001 t about '5 pa f. PhQ PhOIU sulfi e o. n p f h sol ent. xtra ab e yd o arbons- A ti l re specific embodiment comprises .use of about 0.1 part of sulfide to one part of the stated solvent extractable hydroa carbons in the reaction mixture. The reaction is carried out at temperatures varying from about 100 C. .to about 200 C. with the particular temperature employed being commensurate with optimum results obtained front the i po nt of xp di i g ac o min i d r tion f r sinificd d 0 oi nsol e Pr du ts and p imum P sph us c nten As set forth n Said cp nd n appli cat n, the time at r ct n m y be v ied; e e ding on various factors, particularly temperatures employed, with suitable results being usually obtained by carrying out the reaction for about one to about three hours. In illustrative and not limitative aspect, a highly suitable set of conditions as set forth in the copending application for preparation of the acidic phosphorusand sulfur-containing reactant comprises the following:

Temperature About 150 C.

Reaction time About 2 hours.

Weight ratio of reactants" One part of phosphorus sulfide to ten parts of solvent extractable hydrocarbons.

- In accordance therewith, a reaction mixture Was prepared consisting of (a) 15 grams of P285, 180 grams of the aforedefined furfural extract, 180 grams of a light turbine oil (diluent) and 3% by weight (based on the weight of extract) of zinc chloride. The mixture was heated at 150 C. for two hours with continuous stirring, followed by decanting the reacted mixture to remove sludge and unreacted P285 and recovery of a liquid solution comprising about 50% by weight of the acidic phosphorusand sulfur-containing product of reaction between the sulfide and furfural extract, said liquid solution having a neutralization number of 15.4, a sulfur content of 2.12%, and a phosphorus content of 0.89%.

In accordance with this invention, the following examples illustrate the preparation, by use of the aforesaid acidic reaction product, of the novel products of reaction thereof with esters of propenoic acids.

Example I A reaction mixture was prepared consisting of 34.53 grams of the aforesaid acidic solution and 0.817 gram of methacrylate. The mixture was maintained at about 70 C. for one hour during which exothermic reaction occurred (with no substantial evidence of by-product formation) to produce a liquid concentrate (in light turbine oil) of which about 50% by weight was a phosphorusand sulfur-containing product of reaction between the methylacrylate and acidic phosphorusand sulfur-containing acidic reactant. The liquid concentrate had a neutralization number of 6.4.

Example 11 A reaction mixture was prepared consisting of 29.57 grams of the aforesaid acidic liquid solution and 1.43 grams of n-octyl acrylate. The mixture was reacted under the temperature and time conditions set forth in Example I whereby a liquid reaction product having a neutralization number of 6.3 was obtained, said reaction product being a liquid concentrate containing about 50% by weight of the product of reaction between the n-octyl acrylate and the aforedefined acidic PzSs-furfural extract reaction product.

Example III A reaction mixture was prepared consisting of 30.0 grams of the aforesaid acidic solution and 1.57 grams of n-octyl methacrylate. The mixture was reacted under the temperature and time conditions set forth in Example I whereby a liquid reaction product having a neutralization number of 7.7 was obtained, said reaction product being a liquid concentrate containing about 50% by weight of the product of reaction between the n-octyl methacrylate and the aforedefined PzSs-furfural extract reaction product.

Mineral oil compositions were prepared by dissolving, in a furfural refined SAE 30 oil of lubricating grade, 3% by weight of the concentrate (about 50% of active material) of the methacrylate reaction product of Example I, the n-octyl acrylate reaction product of Example II, and the'n-octyl methacrylate reaction product of Example III. To illustrate the effectiveness of such reaction products as oxidation and corrosion inhibitors,

TEST PROCEDURE 250 grams of the oil composition under test, 74-75 square inches of iron wire, 10 square inches of copper wire, and 20 square inches of lead foil surface are placed in a container having an inlet for oxygen and an exit tube for oxidation products and unused oxygen, the aforesaid metals being maintained immersed in the oil. Oxygen is bubbled through the oil (maintained at C. and at atmospheric pressure) at the rate of 30.35 liters per hour and at the end of 20 hours the lead foil surface is cleaned and weighed. The difference between its weight before the test and the loss of weight that occurred during the test is an indication of the corrosive tendency of the oil compositions whereas the difference between the amount of oxygen bubbled through the oil and the amount of unused oxygen is indicative of the oxidation characteristics of the composition.

The following tabulation sets forth data obtained pertaining to lead loss and oxygen absorption characteristics of the aforesaid additive-containing mineral oil compositions under the conditions of the test procedure and for purposes of comparison the tabulation sets forth corresponding lead loss and oxygen absorption values characteristic of a furfural refined SAE 30 oil as used in preparing the compositions but devoid of the additive component of this invention.

As is apparent from the data, the novel products of reaction between the esters of the propenoic acids and acidic reactant imparted to the mineral oil a very substantial improvement in anti-oxidant and anti-corrosion characteristics. 1

In preparation of the acidic reactant by reaction of a phosphorus sulfide with a hydrocarbon mixture as aforedescribed and/ or in carrying out the reaction between the stated esters and the acidic substance, the reactions may be carried out in the presence of additional liquid substances, the presence of which may be desired in the reaction mixture for certain purposes. In illustration, the acidic reactant employed may be a high viscosity material and the reaction thereof with the stated esters may be facilitated by addition of a lower viscosity material (e. g. a diluent) in the reaction mixture. For such purposes low viscosity hydrocarbons such as naphtha, light lubricating oils, and the like may be employed. The added liquid substance may be removed by conventional means following the reaction or may be allowed to remain with the reaction products if it does not deleteriously affect the performance of the desired reaction products in intended usage thereof. In connection therewith, and particularly when the reaction products contemplated herein are to be used as additives for lubricating oil compositions, the reactions are desirably carried out in the presence of a low viscosity mineral oil of lubricating grade whereby, as illustrated in the foregoing examples, the reaction product is obtained as a concentrate useful directly as a lubricating oil additive. Thus, also embodied herein are compositions useful as additives for mineral oils and which compositions are concentrates of the desired reaction products in a suitable liquid vehicle. In such. concentrates, the amount of reaction product may be the major constituent by weight of the composition but it should be understood that' concentrates may also be used' whereint-h'e re'action product does-not constitute themajor-ingredient by weighaJ-"Fhe amount of reaction product actually employd in the concentrateis, therefore, not critic'ahand', from: a practical? matter, the amount of reactioniproducte in-the 'concentrate issuch, that; it will be of 'properviscosity to. facilitate handling and blending with afmineraloil'," i

In the foregoing.- examples, a concentration of about 1.5%. by, weight of active reaction. material (3% of con.-. centrate) was used in.-preparing the oil compositions subj cted to the'described: test procedure. Such concentrations have been: employed for'purposes: of illustration andnot 1i; imes he intention embodi i comp ions 2on ai iug m unts of he. sta ed r action, p o uc o her; th n he amoun spe ifically se r q h- Th oil ompo t on .-arecon emp a edzconta n n t d p o not in smaller or larger amountsgthan specifically setforth sr in fior wi h. he tu l. o entra o mp y d beinadsrwdmt 20.111 ntende usa e of he oi mpo tion, coupled with consideration from an economic viewpoint of the minimum amount of additive to use to im- P the des rei nn penties to. heio li u derhe. con of intended usage. Eor most purposes, however, an amount of the stated reaction produ'c'twithin the range of about L1 to about 20- percent by'weigh-tof the oil compositi'on maybesuitably used.

Y For the mineral oil component of the additive-containing' compo'sitions embodiedherein, usage is contemplated df iniineral oil. fractions that may vary over a rather wide range with respect to properties such as viscosity, viscosity index and others and to which fractions it is desired to impart improved properties. Thus, the mineral oil component may be a highly refined oil, such as those known to the art as solvent extracted oils, acid treated oils, and the like, or fractions derived from petroleum, and useful for particular purposes without resort to extensive refining operations. In a particular embodiment, the mineral oil component is a heavy or light mineral oil fraction, or blend of such fractions, of suitable viscosity characteristics for lubrication purposes, particularly for lubrication of internal combustion engines.

With further reference to the reaction between the stated esters and acidic reactants, the amount of ester employed may be varied depending upon the extent to which it is desired to carry out reaction with the acidic substance. For obtaining optimum conversion of the acidic substance to the substantially neutral products of reaction thereof with the propenoic acid esters, it is preferred to employ an amount of ester sufiicient to enable the reaction to proceed until substantially all of the acidic product has reacted and ob-tainment of such a result is facilitated by using an amount of ester slightly in excess of that theoretically sufiicient to react with the acidic substance. Any unreacted ester may be subsequently removed from the reacted mixture or, in cases wherein the excess ester does not impart undesired properties in the intended usage of the reaction product, it may be allowed to remain therewith. Illustrative of specific embodiments of the invention for preparation of the desired reaction products are the amounts of ester to acidic substance as employed in the foregoing examples and in which the amount of ester employed was substantially equivalent to that theoretically required to react with the amount of acidic substance employed. On the other hand, and in the reaction of certain esters with the stated acidic products wherein complete utilization of the acidic substance is not readily obtainable, or may not be desired, lesser amounts of the esters may be used so as to avoid presence of unreacted esters in the reacted mixture and thus eliminate need for removal of unreacted ester from the reaction mixture when its presence in such a mixture is not desired.

With reference to the reaction that occurs between the stated esters and acidic phosphorusand sulfur-containing reactants, the reaction is of the exothermic type,

proceeds rather rapidly, and in some cases, spontaneously. Hence, relatively:high'temperaturesarenot only not essential, but-are actually='undesired as insome instances;

depending upon the part icul'ar ester employed, undesired.

polymerization of the propenoic acid: ester reactant may be induced before it reacts "with the acidic reactant. Thus, the temperature conditions employed for the reaction depend particularly on the ester used and should be below that sufficient to induce substantial polymerization of the ester reactant. As an-illustrative embodiment, reaction temperatures of from about room temperature up to, but preferably less than, about C; may be employed for reacting the ester with the acidic substance, with a more specific illustration being a temperature of about 70 C. as used in the foregoing examples. Itispreferred that the reactants bemaintained' under reaction conditions until the reaction mixture substantially ceases to decrease in neutralization number." Generally speaking, the time required to attain such a result is not'critical to the extent that a set time can be given irrespective of the particular ester, acidic substances, and reac-' tion conditions employed; As aforesaid, the reaction proceeds rather rapidly; and in some cases spontaneously, and hence extended reaction times are not usually re-' quired. Thus, the most suitable conditions, inclusive of-= time, to effect desired reaction ofparticular esters with particular'acidic substances can bereadily determined by simple experimentation bythose skilled in the art; For most purposes, however, a reaction time up to about 3 hoursusually produces suitable results although in many casesz-i theextent to. Whichffeaction occurs; may be substant'ially; complete after about one-quarter of an hour. A specific illustration thereof is a reaction time of about one hour as used in preparation of the reaction products of Examples I, II and III. Although such reaction conditions normally result in production of the desired products in substantially optimum yields, it should be understood that they are illustrative and not limitative conditions. Hence, the conditions employed may be varied depending upon particular requirements, taking into consideration the particular esters and acidic reactants employed, desired extent of reaction, and the like.

As is apparent from the foregoing examples wherein neutralization values are set forth for the acidic reactant and the desired ester-reacted mixture, the neutralization values for the ester reaction product are substantially lower than the neutralization number of the acidic phosphorusand sulfur-containing reactant. The reaction is believed to be of the addition type between the unsaturated linkage in the propenoic acid esters and certain acidic groups of the phosphorusand sulfur-containing acidic reactant. Hence, the lowering of the neutralization number is clearly the result of a reaction between the propenoic acid ester (neutral products) and the acidic reactant different from the conventional acid-base neutralization reactions employed in the art for neutralizing many of the well-known acidic substances containing phosphorus and sulfur and prepared by reaction of phosphorus sulfides with hydrocarbons. Of considerable importance herein is the discovery that the reaction between the aforesaid esters containing the unsaturated linkage of propenoic acids and the acidic reactant occurs at relatively low reaction temperatures on the order of those set forth hereinbefore, thereby providing for production of the novel effective inhibitors under much lower reaction temperatures than would be expected to be suitable.

Although the present invention has been described in conjunction with certain preferred embodiments thereof, those skilled in the art will readily recognize that variations and modifications can be made. Such modifications and variations are to be considered to be within the purview of the specification and scope of the appended claims. Moreover, it should be understood that mineral oil compositions, as embodied herein, may also contain additional ingredients for imparting other desired properties to the compositions. In illustration, the compositions may contain anti-foam agents, e. g. of the silicone type, viscosity index improvers, e. g. polyacrylates, detergent materials, and the like.

I claim:

1. A lubricating composition comprising a mineral oil in major amount based upon the weight of said composition and a small amount, sufiicient to impart anti-oxidant and anti-corrosion properties to said composition, of an oil-soluble phosphorusand sulfur-containing reaction product of (a) an alkyl ester of an acid from the group consisting of propenoic acid and alkyl-substituted propenoic acids with (b) an acidic, phosphorusand sufurcontaining product of reaction between an excess of a phosphorus sulfide and a predominantly aromatic extract obtained by furfural extraction of a mineral oil.

2. A concentrate, in a mineral lubricating oil vehicle, of an oil-soluble reaction product of (a) an alkyl ester of an acid from the group consisting of propenoic acid and alkyl-substituted propenoic acids with (b) an acidic, phosphorusand sulfur-containing product of reaction between an excess of a phosphorus sulfide and a predominantly aromatic extract obtained by furfural extraction of a mineral oil, said concentrate being adapted for use as an oxidationand corrosion-inhibiting additive for mineral oils.

3. A concentrate, in a mineral lubricating oil vehicle, of an oil-soluble reaction product of (a) an alkyl ester of acrylic acid and (b) an acidic phosphorusand sulfurcontaining product of reaction between an excess of P255 and a predominantly aromatic extract obtained by furfural extraction of a mineral oil fraction.

4. A method for preparing an oil-soluble, substantially neutral phosphorusand sulfur-containing product useful as an anti-oxidant and anti-corrosion additive for mineral oils which comprises subjecting to an elevated temperature a mixture of (a) an acidic phosphorusand sulfur-containing product of reaction between an excess of a phosphorus sulfide and a furfural extract from a mineral oil fraction, and (b) an alkyl ester of an acid from the group consisting of acrylic acid and methacrylic acid in an amount suflicient to neutralize said acidic product, and maintaining said mixture at said elevated temperature for about one quarter of an hour to about three hours until the mixture substantially ceases to decrease in neutralization number, said elevated temperature being below a temperature suflicient to induce substantial polymerization of said ester and not in excess of about 100 C.

References Cited in the file of this patent UNITED STATES PATENTS 2,566,241 Musselman Aug. 28, 1951. 2,571,737 Manteulfel Oct. 16, 1951 2,593,496 Smith et al. Apr. 22, 1952 2,606,182 Musselman Aug. 5, 1952 2,640,053 Hill et al. May 26, 1953 

1. A LUBRICATING COMPOSITION COMPRRISING A MINERAL OIL IN MAJOR AMOUNT BASED UPON THE WEIGHT OF SAID COMPOSITION AND A SMALL AMOUNT, SUFFICIENT TO IMPART ANTI-OXIDANT AND ANTI-CORROSION PROPERTIES TO SAID COMPOSITION, OF AN OIL SOLUBLE PHOSPHORUS- AND SULFUR-CONTAINING REACTION PRODUCT OF (A) AN ALKYL ESTER OF AN ACID FROM THE GROUP CONSISTING OF PROPENOIC ACID AND ALKYL-SUBSTITUTED PROPENOIC ACIDS WITH (B) AN ACIDIC, PHOSPHORUS- AND SULFURCONTAINING PRODUCT OF REACTION BETWEEN AN EXCESS OF A PHOSPHORUS SULFIDE AND A PREDOMINANTLY AROMATIC EXTRACT OBTAINED BY FURFURAL EXTRACTION OF A MINERAL OIL. 